Nanolayer thick film processing system and method

ABSTRACT

A process to deposit a thin film by chemical vapor deposition includes evacuating a chamber of gases; exposing a device to a gaseous first reactant, wherein the first reactant deposits on the device to form the thin film having a plurality of monolayers in thickness; evacuating the chamber of gases; exposing the device, coated with the first reactant, to a gaseous second reactant under a plasma treatment, wherein the thin film is treated by the first reactant; and repeating the previous steps.

[0001] This Application is a Continuation of Application No. 09/954,244filed on Sep. 10, 2001, entitled: “Nanolayer Thick Film ProcessingSystem and Method.”

BACKGROUND

[0002] The present invention relates to semiconductor thin filmprocessing by nanolayer deposition (“NLD”). The fabrication of modemsemiconductor device structures has traditionally relied on plasmaprocessing in a variety of operations such as etching and deposition.Plasma etching involves using chemically active atoms or energetic ionsto remove material from a substrate. Deposition techniques employingplasma includes Chemical Vapor Deposition (“CVD”) and Physical VaporDeposition (“PVD”) or sputtering.

[0003] PVD uses a high vacuum apparatus and generated plasma thatsputters atoms or clusters of atoms toward the surface of the wafersubstrates. PVD is a line-of-sight deposition process that is moredifficult to achieve conformal film deposition over complex topography,such as deposition of a thin and uniform liner or barrier layer over thesmall trench or via of 0.13 μm or less, especially with high aspectratio greater than 4:1.

[0004] In CVD, a gas or vapor mixture is flowed over the wafer surfaceat an elevated temperature. Reactions then take place at the hot surfacewhere deposition takes place. Temperature of the wafer surface is animportant factor in CVD deposition, as it depends on the chemistry ofthe precursor for deposition and affects the uniformity of depositionover the large wafer surface. The high temperatures typically requiredfor CVD deposition may not be compatible with other processes in thesemiconductor process. Moreover, CVD at lower temperature tends toproduce low quality films in term of uniformity and impurities. Moredetails on PVD and CVD are discussed in International Pub. Number WO00/79019 Al or PCT/US00/17202 to Gadgil, the content of which isincorporated by reference.

[0005] In atomic layer deposition (“ALD”), various gases are injectedinto a chamber for as short as 100-500 milliseconds in alternatingsequences. For example, a first gas is delivered into the chamber forabout 500 milliseconds and the substrate is heated, then the first gas(heat optional) is turned off. Another gas is delivered into the chamberfor another 500 milliseconds (heat optional) before the gas is turnedoff. The next gas is delivered for about 500 milliseconds (andoptionally heated) before it is turned off. This sequence is repeateduntil all gases have been cycled through the chamber, each gas sequenceforming a highly conformal monolayer. ALD technology thus pulses gasinjection and heating sequences that are between 100 and 500milliseconds.

[0006] The ALD approach requires a high dissociation energy to break thebonds in the various precursor gases, which can be, for example, silaneand oxygen. ALD thus requires high substrate temperature, for example,on the order of 600-800 degrees Celsius for silane and oxygen processes.

[0007] U.S. Pat. No. 5,916,365 to Sherman, entitled “Sequential chemicalvapor deposition” provides for sequential chemical vapor deposition byemploying a reactor operated at low pressure, a pump to remove excessreactants, and a line to introduce gas into the reactor through a valve.Sherman teaches exposing the part to be coated to a gaseous firstreactant, including a non-semiconductor element of the thin film to beformed, wherein the first reactant adsorbs on the part to be coated. TheSherman process produces sub-monolayers as a result of adsorption. Thefirst reactant forms a monolayer on the part to be coated (aftermultiple cycles), while the second reactant passes through a radicalgenerator which partially decomposes or activates the second reactantinto a gaseous radical before it impinges on the monolayer. This secondreactant does not necessarily form a monolayer, but is available toreact with the monolayer. A pump removes the excess second reactant andreaction products completing the process cycle. The process cycle can berepeated to grow the desired thickness of film.

[0008] U.S. Pat. No. 6,200,893 to Sneh entitled “Radical-assistedsequential CVD” discusses a method for CVD deposition on a substratewherein radical species are used in alternate steps to depositions froma molecular precursor to treat the material deposited from the molecularprecursor and to prepare the substrate surface with a reactive chemicalin preparation for the next molecular precursor step. By repetitivecycles, a composite integrated film is produced. In a preferredembodiment, the depositions from the molecular precursor are metals, andthe radicals in the alternate steps are used to remove ligands remainingfrom the metal precursor reactions, and to oxidize or form a nitride ofthe metal surface in subsequent layers.

[0009] In one embodiment taught by Sneh, a metal is deposited on asubstrate surface in a deposition chamber by: (a) depositing a monolayerof metal on the substrate surface by flowing a molecular precursor gasor vapor bearing the metal over a surface of the substrate, the surfacesaturated by a first reactive species with which the precursor willreact by depositing the metal and forming reaction product, leaving ametal surface covered with ligands from the metal precursor andtherefore not further reactive with the precursor; (b) terminating flowof the precursor gas or vapor; (c) purging the precursor with inert gas;(d) flowing at least one radical species into the chamber and over thesurface, the radical species highly reactive with the surface ligands ofthe metal precursor layer and eliminating the ligands as reactionproduct, and also saturating the surface, providing the first reactivespecies; and (e) repeating the steps in order until a metallic film ofdesired thickness is achieved.

[0010] In another aspect of the Sneh disclosure, a metal nitride isdeposited on a substrate surface in a deposition chamber by: (a)depositing a monolayer of metal on the substrate surface by flowing ametal precursor gas or vapor bearing the metal over a surface of thesubstrate, the surface saturated by a first reactive species with whichthe precursor reacts by depositing the metal and forming reactionproduct, leaving a metal surface covered with ligands from the metalprecursor and therefore not further reactive with the precursor; (b)terminating flow of the precursor gas or vapor; (c) purging theprecursor with inert gas; (d) flowing a first radical species into thechamber and over the surface, the atomic species highly reactive withthe surface ligands of the metal precursor layer and eliminating theligands as reaction product and also saturating the surface; (e) flowingradical nitrogen into the chamber to combine with the metal monolayerdeposited in step (a), forming a nitride of the metal; (f) flowing athird radical species into the chamber terminating the surface with thefirst reactive species in preparation for a next metal deposition step;and (g) repeating the steps in order until a composite film of desiredthickness results.

[0011] The Sneh embodiments thus deposit monolayers, one at a time.Because the objective is to create a thick film, the Sneh process isrelatively time-consuming.

[0012] Atomic layer deposition (ALD or ALCVD) is a modified CVD processthat is temperature-sensitive and flux-independent. ALD is based on aself-limiting surface reaction. ALD provides a uniform deposition overcomplex topography and is temperature-independent, since the gases areadsorbed onto the surface. ALD can occur at lower temperature than CVD,because ALD is an adsorption regime.

[0013] As discussed in connection with the Sherman and Sneh patents,above, the ALD process includes cycles of flowing gas reactant into achamber, adsorbing one sub-monolayer onto the wafer surface, purging thegas reactant, flowing a second gas reactant into the chamber, andreacting the second gas reactant with the first gas reactant to form amonolayer on the wafer substrate. Thick film is achieved by depositionof multiple cycles.

[0014] Precise thickness can be controlled by number of cycles, since asingle monolayer is deposited as a result of each cycle. However, theconventional ALD method is a slow process to deposit films such as thosearound 100 angstroms in thickness. Growth rate of Atomic Layer Epitaxy(“ALE”) TiN for example was reported at 0.2 angstrom/cycle, which istypical of metal nitrides from corresponding chlorides and NH₃.

[0015] The throughput in device fabrication for a conventional ALDsystem is slow. Even if the chamber is designed with minimal volume, thethroughput is still slow due to the high number of cycles required toachieve the desired thickness. Conventional ALD is a slower process thanCVD, with ALD having a rate of deposition almost 10 times slower thanCVD. The process is also chemical-dependent; that is, it is necessary toensure the proper self-limiting surface reaction for deposition.

SUMMARY

[0016] In one aspect, a nano-layer deposition (“NLD”) process ofdepositing a thin film by chemical vapor deposition includes evacuatinga chamber of gases; exposing a device to a gaseous first reactant,wherein the first reactant deposits on the device to form the thin film;evacuating the chamber of gases; and exposing the device, coated withthe first reactant, to a gaseous second reactant under plasma, whereinthe thin film deposited by the first reactant is treated to form thesame materials or a different material.

[0017] Embodiments of the present invention can include one or more ofthe following. The device can be a wafer. The plasma either can enhanceor maintain the thin film conformality. The plasma can be a high densityplasma with density exceeding 5×10⁹ ion/cm³. The reactant can be a metalorganic, organic, to form a thin film of metal, metal nitride, or metaloxide. The second reactant is exposed under pressure, above 100 mT. Thefirst and second reactants react and the reaction creates a newcompound. The thin film thickness is more than one atomic layer inthickness. The thin film thickness can be between a fraction of ananometer and tens of nanometers. The plasma can be sequentially pulsedfor each layer to be deposited. The plasma can be excited with a solidstate radio frequence (“RF”) plasma source, such as a helical ribbonelectrode. The chamber containing the device can be purged.

[0018] The process includes pre-cleaning a surface of a device;evacuating a chamber; stabilizing precursor flow and pressure; exposingthe device to a first reactant, wherein the first reactant deposits onthe device to form the nanolayer thin film having a thickness of morethan one atomic layer; purging the chamber; evacuating the chamber;striking the plasma; performing a plasma treatment on the depositedfilm; exposing the device, coated with the first reactant, to a gaseoussecond reactant under the plasma treatment, wherein the thin filmdeposited by the first reactant is treated to form the same materials ora different material. Repeating the above cycle deposits a thick film,where the thickness is determined by the number of times the cycle isrepeated.

[0019] In another aspect, the deposition steps discussed above can takeplace in multiple chambers. The process includes pre-cleaning of thedevice surface; evacuating the chamber; stabilizing precursor flow andpressure; exposing the device to a first reactant, wherein the firstreactant deposits on the device to form the nanolayer thin film having athickness of more than one atomic layer; purging the chamber; and,evacuating the chamber. The device then is transferred to anotherchamber that is purged and pumped.

[0020] The next step is striking the plasma, followed by performing aplasma treatment on the deposited film; exposing the device, coated withthe first reactant in the first chamber, to a gaseous second reactantunder the plasma treatment in the second chamber, wherein the thin filmdeposited by the first reactant is treated to form the same materials ora different material. Repetition of this cycle in the first and secondchambers deposits a thick film, wherein the thickness of the resultingfilm depends upon the number of cycles of repetitions.

[0021] In another aspect of the invention, an apparatus to performsemiconductor processing includes a high density inductively-coupledplasma source enclosed in a process chamber, wherein a device is exposedinside the chamber to a gaseous first reactant. The first reactantdeposits on the device to form a thin film. After purging, the device,coated with the first reactant, is exposed to a gaseous second reactantunder plasma, wherein the thin film deposited by the first reactant istreated to form the same materials or a different material. The methodcan provide deposition of copper metal from Cu hfacI and plasma (gas),Cu hfacII and plasma (gas), CuI₄ and plasma (gas), CuCl₄ and plasma(gas), and organo metallic and plasma (gas); of titanium nitride fromtetrakisdimethyl titanium (“TDMAT”) and plasma (gas), tetrakisdiethyltitanium (“TDEAT”) and plasma (gas), tetrakis (methylethylamino)titanium (“TMEAT”) and plasma (gas), TiCl₄ and plasma (gas), TiI₄ andplasma (gas), and organo metallic and plasma (gas); of tantalum nitridefrom penta-dimethyl-amino-tantalum (“PDMAT”) and plasma (gas),pentakis(diethylamido)tantalum (“PDEAT”) and plasma (gas), and organometallic and plasma (gas); wherein gas is one of N₂, H₂, Ar, He, NH₃,and combination thereof.

[0022] Implementations of the apparatus can include gas distribution,chuck, vaporizer, pumping port to pump, and port for gas purge.

[0023] Advantages of the system may include one or more of thefollowing. The resulting deposition is highly conformal and is similarin quality to that of ALD. The nanolayer thick film deposition processprovides almost 100% conformal deposition on complex topography as thatin semiconductor devices having 0.1 micron width with an aspect ratiogreater than 8:1. Excellent conformality of film is achieved with NLDsimilar to that of ALD, and far superior than conformality of thick CVDfilm. Further, such conformality is achieved rapidly, since multipleatomic layers up to a few nanometers thick are deposited as a result ofeach cycle of NLD. In contrast, ALD processes only one wafer at a time,requires a small volume, deposits only one monolayer at a time. Theadvantage of NLD over ALD thus is higher throughput over ALD.

[0024] The microstructure of the film resulting from NLD can be of ananocrystalline grain structure in an amorphous matrix using the NLDtechnique, since a film of more than a monolayer to a few nanometerthick is deposited in each cycle. This structure is not typical ofconventional CVD or PVD. The surface morphology of the films depositedby NLD is also smoother than that of films deposited by conventionalCVD. This microstructure and morphology can be ideal for certainapplications. In the application of copper diffusion barrier thin filmdeposition, this microstructure of the barrier thin film is a key to theresistance to copper. In fact, our initial data show that our NLD TiNfilm deposited from TDMAT precursor and N₂ plasma has superior barrierproperties to PVD TiN, PVD TaN, or conventional CVD TiN. Additionally,the low temperature of the NLD deposition process, which can be lowerthan that of CVD, is consistent with the processing requirements ofadvanced films, such as low-k dielectric.

[0025] The precursors or gases usable in the NLD process are not limitedto those having the self-limiting surface reactions, since NLD is adeposition process. NLD thus employs a much broader spectrum ofprecursors and can be used to deposit a vast number of film materialsfrom a variety of available precursors. Since NLD has high throughput,minizing the chamber volume, as is necessary in ALD, is not necessary.Consequently, a conventional CVD chamber can be used to achieve highlyconformal, high quality, high throughput films.

[0026] Other advantages of the system may include one or more of thefollowing. The helical ribbon provides a highly uniform plasma whichdoes not require a chamber with a small volume. The system enables highprecision etching, deposition, or sputtering performance. This isachieved using the pulse modulation of a radio frequency-powered plasmasource, which enables a tight control over the radical production ratioin plasmas, the ion temperature, and charge accumulation. Also, sincethe time for accumulation of charges in a wafer is on the order ofmilli-seconds, the accumulation of charges to the wafer is suppressed bythe pulse-modulated plasma on the order of micro-seconds, and thisenables the suppression of damage to devices on the wafer caused by thecharge accumulation and of notches caused during the electrode etchingprocess. The system requires that the substrate be heated to arelatively low temperature, such as 400 degrees Celsius.

[0027] Yet other advantages may include one or more of the following.The system attains highly efficient plasma operation in a compactsubstrate process module that can attain excellent characteristics foretching, depositing or sputtering of semiconductor wafers, asrepresented by high etch rate, high uniformity, high selectivity, highanisotropy, and low damage. The system achieves high density and highlyuniform plasma operation at low pressure for etching substrates and fordeposition of films on to substrates. Additionally, the system iscapable of operating with a wide variety of gases and combinations ofgases, including highly reactive and corrosive gases.

BRIEF DESCRIPTION OF THE DRAWINGS

[0028]FIGS. 1A-1E show exemplary embodiments of a plasma processingsystem with a helical ribbon.

[0029]FIGS. 2A-2C show more details of the helical ribbon of FIG. 1.

[0030]FIG. 3 shows a flowchart of one exemplary semiconductormanufacturing process using the system of FIG. 1.

[0031]FIGS. 4A-4B show exemplary generator embodiments.

[0032]FIG. 5 shows a multi-chamber semiconductor processing system.

[0033]FIG. 6 shows a diagram of an exemplary apparatus for liquid andvapor precursor delivery.

[0034]FIGS. 7A-7B show two operating conditions of an embodiment toperform plasma deposition.

[0035]FIG. 8 shows a flow chart of a nanolayer thick film process inaccordance with one embodiment of the invention.

[0036]FIG. 9 shows an SEM of an exemplary wafer created in accordancewith one embodiment of the invention.

[0037]FIG. 10 shows a plot of film resistance increase as a function oftime for an exemplary process recipe.

DESCRIPTION

[0038]FIG. 1A shows an exemplary plasma processing system 100 with aprocessing chamber 102. The process chamber 102 has a chamber bodyenclosing components of the process chamber such as a chuck 103supporting a substrate 105. The process chamber typically maintainsvacuum and provides a sealed environment for process gases duringsubstrate processing. The process chamber periodically must be accessedto cleanse the chamber. An opening typically is provided for maintenanceat the top of the process chamber that is sufficiently large to provideaccess to its the internal components.

[0039] The chamber 102 includes a plasma excitation circuit 106 drivenby a solid-state plasma generator 110 with fast ignition capability. Onecommercially available plasma source is the Litmas source, availablefrom LITMAS Worldwide of Matthews, North Carolina. The generator 110includes a switching power supply 112 that is connected to analternating current (AC) line. The power supply 112 rectifies AC inputand switches the AC input to drive an RF amplifier 116. The RF amplifier116 operates at a reference frequency (13.56 MHz, for example) providedby a reference frequency generator 104. The RF amplifier 116 drivescurrent through a power measurement circuit 118 that provides feedbacksignals to a comparator 120 and to the reference frequency generator104. In this embodiment, power is measured only once, and theinformation is used to control the RF amplifier 116 gain, as well as atuning system if needed. Power is then delivered to an output matchsection 122, which directly drives the plasma excitation circuit 106. Inone embodiment (FIG. 1C), the plasma excitation circuit 106 uses helicalribbon electrodes 170 in the chamber. However, other equivalent circuitscan be used, including (FIG. 1B) an external electrode of capacitancecoupling or inductance coupling type, for example.

[0040] Positioned above the helical ribbon electrodes 170 is a heatexchanger 182 that removes heat from the helical ribbon electrodes 170during operation. In one embodiment, the heat exchanger is a pipe thatcirculates fluid to remove heat. The fluid moves through the pipe andthe helical ribbon electrodes 170. Fluid then enters the heat exchanger182 and traverses through a loop. Thermal energy in the form of heattransfers to fluid in another loop, which is cooler in temperature anddraws heat away from the heat in the fluid in the first loop. In aspecific embodiment, cooling fluid enters and leaves the heat exchanger182.

[0041] A controller 130 generates a periodic pulse and drives one inputof the frequency reference 104. The pulse effectively turns on or offthe plasma generation. One embodiment of the controller 130 generates apulse with a frequency of ten hertz (10 Hz) or less. In anotherembodiment, the pulse generated has a pulse-width of approximately twohundred fifty (110) millisecond and the pulse is repeated approximatelyevery fifty (50) microseconds.

[0042] Turning now to FIG. 1B, a second embodiment is shown. FIG. 1Bincludes a helical ribbon electrode 170 connected to a generator 110.The helical ribbon electrode 170 rests above a dielectric wall 154. Thedielectric wall 154 rests above a chamber 102 and is supported bychamber walls 158. The dielectric wall 154 allows the energy generatedfrom the generator 110 to pass through to generate a plasma inside thechamber 102. The dielectric materials can be any non-metallic materialssuch as ceramic, glass, quartz, or plastic.

[0043]FIG. 1C shows a third embodiment where the helical ribbonelectrode 170 is positioned inside a chamber 102 with walls 158. Thewalls 158 have an electrical feed through 155, through which thegenerator 110 can drive the helical ribbon electrode 170. There need notbe a dialectric plate 154.

[0044]FIG. 1D shows a fourth embodiment where the helical ribbonelectrode 170 wraps around a tubular dielectric wall 154. A chamber 102is positioned within the helical ribbon electrode 170 and the tubulardielectric wall 154, through which the generator 110 can drive thehelical ribbon electrode 170.

[0045]FIG. 1E shows a fifth embodiment optimized for pulsed processing.This embodiment has a helical ribbon electrode 170 connected to agenerator, with the helical ribbon resting above a dialectric wall 154.This embodiment further has an elongated chamber 102 with a small volume186 above a wafer 183. The volume is dependent on the diameter of thewafer 183 and the distance between the helical ribbon electrode 170 andthe wafer. Typically, the distance is less than five (5) inches, but canalso be between one and three inches. The helical ribbon electrode 170in turn is driven by the generator 110. The large ratio of the width tothe thickness of the helical ribbon electrode allows the short distanceand still offers the plasma uniformity required on the wafer surface.

[0046] The characteristics of a film deposited by the above techniquesdepend upon the electron temperature in the plasma, the energy of ionincident on a substrate, and the ions and radicals produced in thevicinity of an ion sheath. The electron temperature distribution in theplasma, the kinds of ions and radicals produced in the plasma, and theratio between the amount of ions and radicals, can be controlled bymodulating a high-frequency voltage in the same manner explained withrespect to plasma etching. Accordingly, when conditions for depositing ahigh quality film are known, the discharge plasma is controlled by amodulated signal according to the present invention, so that the aboveconditions are satisfied. Thus, the processing characteristics withrespect to film deposition can be improved.

[0047]FIGS. 2A-2C show more details of the helical ribbon electrode 170.In FIG. 2A, an elongate conductive coil 172 insulated by a sheet ofdielectric material 174 is wound to form a cylindrical helix. The twosides of the helix are then compressed into planes such that the coil172 surfaces in each side lie flat and engage the adjacent side of thesheet of dielectric material 174.

[0048] The ribbon coil 172 can have about three to ten turns and can bemade of any conductive, ductile metal, such as copper or aluminum. Thecoil 172 has a width that is substantially greater than its thickness.Preferably, the width is approximately one hundred times the thickness,although the ratio of width w to thickness t may conceivably range from1 to 10000, depending on mechanical considerations and/or electricalparameters. Mechanical considerations affecting the optimumwidth:thickness ratio include, for example, build height and turnsratio. In one embodiment, the coil 172 can have three turns, with thewidth of the coil 172 at about 40 millimeters and a thickness at aboutone millimeter.

[0049] Electrical parameters affecting the optimum width:thickness ratioinclude, for example, electrical resistance, skin effect, and proximityeffect. During manufacturing, the conductive coil 172 and dielectricsheet 174 are wound in one continuous direction on a cylindrical mandreland then compressed into a plane. With the exception of the outermostcoil layers, the compressed coil engages on one side a sheet ofdielectric material, and on the other side a sheet of dielectricmaterial. Bends (not shown) are formed in the ribbon coil 172 near theends so that the ends project radially from conductive coil 172 forexternal connection.

[0050] The conductive coil 172 is then compressed into a pancake withmultiple layers such that the coils lie flat and engage one side of thedielectric material sheet 174. The compressed sides form a flat coil.The width of the conductive coil 172 is less than the width of thedielectric material sheet 174 such that, when compressed, the interioror exterior of adjacent coil surfaces do not touch. The ends of theribbon coil 172 project from the outer coil surfaces, where they can beattached to other electrical components.

[0051] The coil 172 can be adhered to sheet 174 of dielectric materialby at least two methods. One method is to provide a sheet of dielectricmaterial that is coated on both sides with thermal-set adhesive. Aftercompression, a winder is heated sufficiently to activate the thermal-setadhesive to adhere the coil 172 to the dielectric material sheet 174. Asecond method is to adhere the coil 172 to sheet 174 by insulatingadhesive tape disposed between each coil layer. In one embodiment, thehelical ribbon electrode 170 is available from LITMAS Corporation ofMatthews, North Carolina.

[0052] The helical ribbon electrode 170 enhances the uniformity of powerdensity due to its width:thickness ratio. Power transmittance is higherbecause the helical ribbon electrode 170 is closer to the chamber. Theresult is reduced power loss. The helical ribbon electrode 170 is low inprofile, and supports a high density, low profile semiconductorprocessing system.

[0053]FIG. 3 shows a flowchart of one exemplary semiconductormanufacturing process using the system 100 of FIG. 1. First, a wafer ispositioned inside the chamber (step 200). Next, suitable processing gasis introduced into the chamber (step 202). The chamber is pressurized toa pressure level such as four hundred millitorr (400 mT). The pressurelevel can range between about one hundred millitorr (100 mT) to aboutten torr (10T) (step 203). The controller 130 (depicted in FIG. 1A) isturned on periodically, in accordance with a process activation switchto drive the desired process (step 204). The particular type of processto be performed affects the process activation switch choice. The choiceof activation switch for any device fabrication process, regardless ofwhether the process is a deposition or etch process, also maysignificantly affect the final semiconductor device properties. At theconclusion of the processing of one layer of material, the gas in thechamber is purged (step 206), and the chamber is ready to accept furtherprocessing. For the next layer of material, suitable processing gas isintroduced into the chamber (step 208). The chamber is pressurized to apressure level above approximately one hundred millitorr (100 mT), andthe controller 130 is periodically turned on to drive the desiredprocess (step 210). At the conclusion of the processing of the secondlayer of material, the gas in the chamber is purged (step 212), and thechamber is ready to accept another processing gas to process and depositanother layer of material. This process is repeated for each layer inthe multi-layer film.

[0054] In another embodiment, thin film is deposited using chemicalvapor deposition by evacuating a chamber of gases; exposing a part to becoated to a gaseous first reactant, wherein the first reactant depositson the part to form the thin film; evacuating the chamber of gases;exposing the part, coated with the first reactant, to a gaseous secondreactant of plasma at a high pressure, wherein the plasma converts thesecond reactant on the part to one or more elements, wherein the thinfilm deposited is treated; and, evacuating the chamber of gases.

[0055]FIG. 4A shows one exemplary controller 130. The controller 130includes a computer 131 driving a digital to analog converter (“DAC”)133. The DAC 133 generates shaped waveforms and is connected to ahigh-voltage isolation unit 135 such as a power transistor or a relay todrive the plasma generator 110. The controller 130 can generate variouswaveforms such as a rectangular wave and a sinusoidal wave, and moreovercan change the period and amplitude of such waveforms. Further, in theabove explanation, the RF power supplied to a plasma is modulated with arectangular wave. The modulation wave form is determined in accordancewith known factors, including: a desired ion energy distribution; adesired electron temperature distribution; and a desired ratio betweenthe amount of the desired ion and the amount of the desired radical. Theuse of a rectangular wave as the modulation waveform is advantageousbecause a processing condition can be readily set and the plasmaprocessing can be readily controlled. It is to be noted that since therectangular wave modulates the signal from the RF source in a discretefashion, the rectangular wave can readily set the processing condition,as compared with the sinusoidal wave and the compound wave of it.Further, the pulse generator can also generate amplitude-modulatedsignals in addition, or in combination with, the frequency-modulatedsignals.

[0056]FIG. 4B shows an exemplary embodiment that uses a timer chip suchas a 137 timer, available from Signetics of Sunnyvale, CA. The timerchip 137 is preconfigured through suitable resistive-capacitive (“RC”)network to generate pulses at specified intervals. The timer chip 137generates shaped waveforms and is connected to a high-voltage isolationunit 135, such as a power transistor or a relay, to drive the plasmagenerator 110 (as in FIG. 1A), as discussed above.

[0057] Referring now to FIG. 5, a multi-chamber semiconductor processingsystem 300 is shown. The processing system 300 has a plurality ofchambers 302, 304, 306, 308 and 310 adapted to receive and processwafers. Controllers 322, 324, 326, 328 and 330 control each of thechambers 302, 304, 308 and 310, respectively. Additionally, a controller321 controls another chamber, which is not shown.

[0058] Each of chambers 302, 304, 306, 308, 310 has a lid over eachchamber body. During maintenance operations, the lid can be actuatedinto an open position so that components inside the chamber bodies canreadily be accessed for cleaning or replacement as needed.

[0059] The chambers 302, 304, 306, 308, 310 are connected to a transferchamber (not visible) that receives a wafer. The wafer rests on top of arobot blade or arm (not depicted). The robot blade receives wafer froman outside processing area.

[0060] The transport of wafers between processing areas entails passingthe wafers through one or more doors separating the areas. The doors canbe load lock chambers 360, 362 for passing a wafer-containing containeror wafer boat that can hold about twenty-five wafers in one embodiment.The wafers are transported in the container through the chamber from onearea to another area. The load lock can also provide an air circulationand filtration system that effectively flushes the ambient airsurrounding the wafers.

[0061] Each load lock chamber 360, 362 is positioned between sealedopening (not visible), and provides the ability to transfersemiconductor wafers between fabrication areas. The load locks 360, 362can include an air circulation and filtration system that effectivelyflushes the ambient air surrounding the wafers. The air within each loadlock chamber 360, 362 can also be purged during wafer transferoperations, significantly reducing the number of airborne contaminantstransferred from one fabrication area into the other. The load lockchambers 360, 362 can also include pressure sensors that take airpressure measurements for control purposes.

[0062] During operation, a wafer cassette on a wafer boat is loaded atopenings in front of the system to a load lock through the load lockdoors. The doors are closed, and the system is evacuated to a pressureas measured by the pressure sensors. A slit valve (not shown) is openedto allow the wafer to be transported from the load lock into thetransfer chamber. The robot blade takes the wafer and delivers the waferto an appropriate chamber. A second slit valve opens between thetransfer chamber and process chamber, and wafer is brought inside theprocess chamber.

[0063] Containers thus remain within their respective fabrication areasduring wafer transfer operations, and any contaminants clinging tocontainers are not transferred with the wafers from one fabrication areainto the other. In addition, the air within the transfer chamber can bepurged during wafer transfer operations, significantly reducing thenumber of airborne contaminants transferred from one fabrication areainto the other. Thus during operation, the transfer chamber provides ahigh level of isolation between fabrication stations.

[0064]FIG. 6 shows an exemplary apparatus 400 for liquid and vaporprecursor delivery using system 100. The apparatus 400 includes achamber 402 that can be a CVD or NLD chamber. The chamber 402 includes achamber body 458 that defines an evacuable enclosure for carrying outsubstrate processing. The chamber body 458 has a plurality of portsincluding at least a substrate entry port that is selectively sealed bya slit valve and a side port through which a substrate support membercan move. The apparatus 400 also includes a vapor precursor injector 446connected to the chamber 402, and a liquid precursor injector 442connected to the chamber 402.

[0065] In the liquid precursor injector 442, a precursor 460 is placedin a sealed container 461. An inert gas 462, such as argon, is injectedinto the container 461 through a tube 463 to increase the pressure inthe container 461 to cause the liquid precursor 460 to flow through atube 464 when a valve 465 is opened. The liquid precursor 460 is meteredby a liquid mass flow controller 466 and flows into a tube 467 and intoa vaporizer 468, which is attached to the CVD or NLD chamber 402. Thevaporizer 468 heats the liquid causing the precursor 460 to vaporizeinto a gas 469 and flow over a substrate 483, which is heated to anappropriate temperature by a susceptor to cause the vaporized precursor460 to decompose and deposit a layer on the substrate 483. The chamber402 is sealed from the atmosphere with exhaust pumping 475 and allowsthe deposition to occur in a controlled partial vacuum.

[0066] In the vapor precursor injector 446, a liquid precursor 488 iscontained in a sealed container 489 which is surrounded by a temperaturecontrolled jacket 423 and allows the precursor temperature to becontrolled to within 0.1° C. A thermocouple (not shown) is immersed inthe precursor 488 and an electronic control circuit (not shown) controlsthe temperature of the jacket 423, which controls the temperature of theliquid precursor and thereby controls the precursor vapor pressure. Theliquid precursor can be either heated or cooled to provide the propervapor pressure required for a particular deposition process. A carriergas 480 is allowed to flow through a gas mass flow controller 482, whenvalve 457 and either valve 492 or valve 495, but not both, is opened.Also shown is one or more additional gas mass flow controllers 486 toallow additional gases 484 to also flow when valve 487 is opened, ifdesired. Additional gases 497 can also be injected into the vaporizer468 through an inlet tube 498 attached to valve 479, which is attachedto a gas mass flow controller 499. Depending on its vapor pressure, acertain amount of precursor 488 will be carried by the carrier gases 480and 484, and exhausted through tube 493 when valve 492 is open.

[0067] After the substrate has been placed into the chamber 402, it isheated by a heater as discussed above. After the substrate has reachedan appropriate temperature, valve 492 is closed and valve 495 is opened,allowing the carrier gases 480 and 484 and the precursor vapor to enterthe vaporizer 468 through the attached tube 496. Once the precursor 488is vaporized, it is carried through the mass flow controller 491. Such avalve arrangement prevents a burst of vapor into the chamber 402. Avapor distribution system, such as a shower head 468 or a distributionring (not shown), is used to evenly distribute the precursor vapor overthe substrate 483. After a predetermined time, depending on thedeposition rate and the thickness required for the initial filmdeposition, valve 495 is closed and valve 492 is opened. The flow rateof the carrier gas can be accurately controlled to as little as 1 sccmper minute and the vapor pressure of the precursor can be reduced to afraction of an atmosphere by cooling the precursor 488. Such anarrangement allows for accurately controlling the deposition rate toless than 10 angstroms per minute, if so desired.

[0068]FIGS. 7A-7B show two operating conditions of an embodiment 500 toperform high pressure barrier pulsed plasma atomic layer deposition.FIG. 7A shows the embodiment 500 in a deposition condition, while FIG.7B shows the embodiment 500 in a rest condition. Referring now to FIGS.7A-7B, a chamber 502 receives gases through one or more gas inlets 467,496, 498, as shown in FIG. 6. A solid state plasma generator 510 ismounted on top of the chamber 502 and one or more plasma excitationcoils 570 are positioned near the gas inlets 568. A liquid precursorsystem 542 introduces precursor gases through a vaporizer 568 into thechamber 502 using a precursor distribution ring 568 (see also 469 inFIG. 6).

[0069] A chuck 503 movably supports a substrate 583. In FIG. 6A, thechuck 503 and the substrate 583 are elevated and ready for deposition.The substrate 583 is positioned inside the chamber. Suitable processinggas is introduced into the chamber through the inlets 568, and a pulsedplasma controller 510 is periodically turned on in accordance with aprocess activation switch to drive the desired process. The particulartype of process to be performed affects the process activation switchchoice. The choice of activation switch for any device fabricationprocess, regardless of whether the process is a deposition or etchprocess, also may significantly affect the final semiconductor deviceproperties. At the conclusion of the processing of one layer ofmaterial, the gas in the chamber 502 is purged, and the chamber 502 isready to accept further processing. This process is repeated for eachlayer in the multi-layer wafer. At the conclusion of deposition of alllayers, the chuck 503 is lowered and the substrate 583 can be removedthrough an opening 511.

[0070] The system allows the substrates to have temperature uniformitythrough reliable real-time, multi-point temperature measurements in aclosed-loop temperature control. The control portion is implemented in acomputer program executed on a programmable computer having a processor,a data storage system, volatile and non-volatile memory and/or storageelements, at least one input device, and at least one output device.

[0071] Each computer program is tangibly stored in a machine-readablestorage medium or device (e.g., program memory or readable disk)readable by a general or special purpose programmable computer, forconfiguring and controlling operation of a computer when the storagemedia or device is read by the computer to perform the processesdescribed herein. The invention may also be considered to be embodied ina computer-readable storage medium, configured with a computer program,where the storage medium so configured causes a computer to operate in aspecific and predefined manner to perform the functions describedherein.

[0072] The results of one experimental run are discussed next. First, anexemplary process recipe for depositing titanium nitride is detailedbelow: Process step time function Pressue (T) carrier liquid N₂ plasmaH₂ chuck Pre-clean 1 4 s Pump 0 0 0 0 0 0 up 2 3 s Strike 0 0 0 5 1200 0up 3 15 s Plasma 0.4 100 0 5 1200 0 up deposition 4 10 s Stab 1.5 100 100 0 0 up 5 6 s dep1 1.5 100 10 0 0 0 up 6 3 s Purge 0 100 0 0 0 0 up 7 3s Pump 0 0 0 0 0 0 up 8 3 s Strike 0 0 0 5 1200 0 up 9 30 s plasma1 0.4100 0 5 1200 0 up 10 loop to step 4 (stab) Cooling 11 1 s Plasma off 0100 0 0 0 0 up 12 30 s Cool 0 100 0 0 0 0 down

[0073] Steps 1-3 relate to pre-cleaning of the substrate surface. Inthese steps, the chamber is brought to a low pressure by evacuationpumping for 4 seconds. Next, the plasma is struck for 3 seconds. Thestrike operation allows the plasma to be started at low pressure andthen the plasma is turned on for 15 seconds at a higher pressure. Theplasma is turned on at a pressure of 0.4 Torr to provide high pressure,high density plasma for isotropic surface conditioning.

[0074] After pre-cleaning, the flow and pressure is stabilized for 10seconds. A first deposition step is performed for 6 seconds. The chamberis purged with carrier gas or an inert gas such as N₂ for 3 seconds, andthe valve to the pump is open for 3 seconds to remove all liquidprecursors and/or vapor residues in the chamber. A plasma strikeoperation is performed for 3 seconds, and plasma treatment for the firstdeposition is activated for 30 seconds at a pressure of 0.4 Torr. Foreach additional deposition, the process loops back to step 4. When thewafer deposition is complete, the plasma is turned off for one secondand the substrate is optionally cooled down for 30 seconds before it isremoved from the chamber. The timing of the steps are illustrative andcan be varied from as low as a half a second to as high as five minutes,depending on the desired property of the film and the film quality,among others.

[0075]FIG. 8 shows a flow chart of a nanolayer thick film process inaccordance with one embodiment of the invention. NLD technique is acombination of ALD and CVD and thus makes use of the advantages of bothALD and CVD. The process of FIG. 8 includes evacuating a chamber ofgases (step 602); exposing a device to a gaseous first reactant, whereinthe first reactant deposits on the device to form the thin film (step604); purging the chamber and evacuating the chamber of gases (step606); and exposing the device, coated with the first reactant, to agaseous second reactant under plasma, wherein the thin film deposited bythe first reactant is treated to form the same materials or a differentmaterial (step 608). The process can be repeated if the decision tocontinue (step 610) is made. Alternatively, the process can beterminated (step 612).

[0076] In one embodiment of the process of FIG. 8, a first gas reactantis flowed over a wafer surface and deposits on the wafer. The amount ofthe first gas reactant into the chamber is controlled by a liquid flowcontroller (“LFC”) and valves to control the deposition of a layer thatis more than a monolayer thick to a few nanometers thick. The firstreactant can then be purged with inert gas, and pumped. A secondreactant is flowed into the chamber to react with the first reactant toform a layer that is more than a monolayer thick to a few nanometersthick. A high density plasma may be used during the second reactantinjection to enhance or maintain the conformality of the deposited filmon complex topography. The density of the deposited film may alsoincrease after the high density plasma treatment during the secondreactant injection. The second reactant then is optionally purged andremoved by pumping. Other reactants can be flown in to react withdeposited and reacted film to form a final film. The above steps arerepeated to form a thick film that is a multiple in thickness of thelayer that is more than a monolayer thick to a few nanometer thick. Thethickness of each repeat or cycle deposited thus is more than amonolayer thick, but the subsequent reactants under high density plasmacan still react with the full thickness of the deposited film to achievea high quality and uniform film.

[0077] For the above NLD process, the materials deposit on the wafer inthe deposition temperature regime and not by adsorption. The temperaturein some cases is higher than the temperature of the ALD process, butlower than that of the conventional CVD process and adequate for othersemiconductor processes. Since the NLD process is a deposition processrather than a self-limiting surface adsorption reaction process, thedeposition rate to achieve a thickness of more than a monolayer to a fewnanometers is controlled by an LFC and valves. The deposition rate inNLD process can also be controlled by tailoring the wafer temperature orchuck (or susceptor) temperature, process pressure, and gas flow rate,among others.

[0078] The process of deposition of nanolayer thick film provides almostcompletely conformal deposition on complex topography as that insemiconductor devices having 0.1 micron width with an aspect ratio ofmore than 8:1. Excellent conformality of film is achieved with NLDsimilar to that of ALD, and far superior than conformality of thick CVDfilm.

[0079] Where a film of a few to 10 nanometers thick is required, the NLDprocess provides higher throughput, since in each NLD cycle, a film ofmore than a monolayer to a few nanometers thick film is deposited. Sincethe NLD process has high throughput, the minimal volume constraint as inthe ALD process is not necessary, and a conventional CVD chamber can beused to achieve highly conformal, high quality, high throughput films.

[0080] Since a film of more than a monolayer to a few nanometers thickis deposited in each cycle, the microstructure of the resulting film canbe of nanocrystalline structure in an amorphous matrix, which can beideal for certain applications, such as diffusion barrier for copper.

[0081] Since NLD is a deposition process, the precursors or gases arenot limited to only those that deposit by a self-limiting surfacereaction. NLD thus is not limited to ALD precursors and can be used todeposit a vast number of film materials from currently availableprecursors.

[0082]FIG. 9 shows a Transmission Electron Micrograph (“TEM”) of astructure that is deposited with a thin film in accordance with thesteps discussed above. The structure has a height of approximately 800nm, and an average width of approximately 90 nm. The aspect ratio of thestructure is thus more than 8:1. Also seen in the Figure is 9 nm thinfilm of TiN that is deposited film in accordance with the stepsdiscussed above onto the structure from the top. As shown therein, thethickness of the deposited film is approximately the same on top, on thesidewalls, and on the bottom of the structure, within the measurementapproximation. Close examination of the micrograph indicates that theconformality of the deposited film is close to 100%. In comparison,conventional deposition methods using low densityplasma—capacitance-coupled plasma typically results in a directional,non-isotropic bombardment of plasma treatment, resulting innon-treatment of the sidewalls.

[0083]FIG. 10 shows a plot of film resistance increase of the titaniumnitride (“TiN”) thin films as a function of time for the above process.The demonstrated TiN film was deposited using TDMAT precursor and N₂flow under plasma treatment in accordance with the steps discussedabove. The wafer temperature during deposition was approximately 325° C.The resistivity of the bulk film is approximately 300 μOhm-cm. As showntherein, the sheet resistance increases approximately 4.2% for sample 1,which has a thickness of approximately 10 nm, approximately 3.5% forsample 2, which has a thickness of approximately 20 nm, and less than 2%for sample 3, which has a thickness of approximately 60 nm, over aperiod of approximately twenty four hours. The plot shows that the filmis stable with minor resistance fluctuations. The increase in resistancein these TiN films deposited with a thin film following the stepsdisclosed above is significantly lower than reported values. K.C. Parket al. reported a 100 nm thick TiN film deposited using TDMAT precursorin an N₂ ion-beam-induced plasma CVD system increases almost 10% inresistivity after 24-hour air exposure. The conformality of the filmsalso degrades to below 5%, in contrast to almost 100% conformalityachieved with the film deposited in accordance with the steps discussedabove. The advantage of using TDMAT precursor for TiN deposition is thelower deposition temperature compared to other precursors such as TiCl₄and NH₃ which require a deposition temperature of higher than 600degrees Celsius for good quality TiN film. Thermal TDMAT and TDEATprocess produce highly conformal TiN films but with high carboncontamination, high resistivity of more than 2000 μOhm-cm, and unstableafter air-exposure. Reactions of these films with NH₃ in various plasmareduce the impurities and resistivity; the conformality, however, isalso degraded. Nitrogen plasma treatments also have been studied withTDMAT precursor. In general, however, conventional deposition methodsusing low density plasma—capacitance coupled plasma in down-stream orparallel plate configuration typically result in a directional,non-isotropic bombardment of plasma treatment, resulting innon-treatment of the sidewalls. More details on TiN deposition usingdifferent precursors and plasma treatments are discussed in K.C. Park etal., the content of which is incorporated by reference.

[0084] It should be realized that the above examples represent a few ofa virtually unlimited number of applications of the plasma processingtechniques embodied within the scope of the present invention.Furthermore, although the invention has been described with reference tothe above specific embodiments, this description is not to be construedin a limiting sense. For example, the duty ratio, cycle time and otherparameters and conditions may be changed to obtain desired wafercharacteristics.

[0085] Various modifications of the disclosed embodiment, as well asalternative embodiments of the invention, will become apparent topersons skilled in the art upon reference to the above description. Theinvention, however, is not limited to the embodiment depicted anddescribed. For instance, the radiation source can be a radio frequencyheater rather than a lamp. Hence, the scope of the invention is definedby the claims that follow. It is further contemplated that the claimswill cover such modifications that fall within the true scope of theinvention.

What is claimed is:
 1. A process to deposit a thin film on a device bychemical vapor deposition, comprising: a. exposing the device to agaseous first reactant, wherein the first reactant deposits on thedevice to form a first layer that can be other than a monolayer; b.performing a plasma treatment on the deposited film; c. exposing thedevice, with the first layer deposited, to a gaseous second reactantunder the plasma treatment to deposit the gaseous second reactant; andd. repeating steps (a) and (c) until the thin film, comprising aplurality of layers, is deposited.
 2. The process of claim 1, whereinthe device is a wafer.
 3. The process of claim 1, wherein the plasmatreatment is capable of at least one of enhancing and maintaining atleast one of conformality and density of the thin film.
 4. The processof claim 1, wherein the plasma is a high density plasma with greaterthan 5×10⁹ ion/cm³.
 5. The process of claim 1, wherein at least one ofthe gasous first reactant and the gaseous second reactant comprises ametal organic reactant.
 6. The process of claim 1 wherein at least oneof the gaseous first reactant and the gaseous second reactant comprisesa metal organic reactant.
 7. The process of claim 1, wherein one of thereactants comprises an organic reactant.
 8. The process of claim 1,wherein the thin film comprises a metal film.
 9. The process of claim 1,wherein the thin film is selected from the group consisting of a metalnitride film and a metal oxide film.
 10. The process of claim 1, whereinexposing the device, with the first layer deposited, to the secondreactant occurs under pressure above one hundred militorr (100 mT). 11.The process of claim 1, further comprising pressurizing the chamber to apressure above one hundred militorr (100 mT).
 12. The process of claim11, wherein reacting the first reactant and second reactant creates anew compound.
 13. The process of claim 1, wherein the thin filmthickness is between a fraction of a nanometer and ten nanometers. 14.The process of claim 1 further comprising exciting the plasma with asolid state RF plasma source.
 15. The process of claim 15 wherein theprocess further comprises using a helical ribbon electrode as the solidstate RF plasma source.
 16. The process of claim 1, further comprisingsequentially pulsing the plasma for each layer to be deposited.
 17. Theprocess of claim 1, further comprising purging a chamber of the firstreactants.
 18. A process to deposit a thin film by chemical vapordeposition, comprising: (a) pre-cleaning a surface of a device; (b)evacuating a chamber of gases; (c) exposing the device to a gaseousfirst reactant in the chamber, wherein the first reactant deposits onthe device to form a layer having a thickness of other than a monolayer;(d) evacuating the chamber of gases; (e) striking a plasma; (f) exposingthe device, coated with the first reactant, to a gaseous second reactantunder the plasma so that the layer deposited by the first reactant istreated; and (g) repeating steps (c)-(f) until the thin film comprisinga plurality of layers is deposited.
 19. An apparatus to performnano-layer deposition, comprising: an inductively coupled plasmagenerator; and a process chamber, in which to expose a device to agaseous first reactant, wherein the first reactant deposits on thedevice to form a layer having a thickness of more than a monolayer, andwherein the chamber is used to expose the device, coated with the firstreactant, to a gaseous second reactant under a plasma, so that the layerdeposited by the first reactant is treated.
 20. A process to deposit athin film including a plurality of layers on a device by chemical vapordeposition, the process comprising: a. exposing the device to a gaseousfirst reactant, wherein the first reactant deposits on the device toform a layer; b. exposing the device, coated with the first reactant, toa gaseous second reactant under a plasma treatment, wherein the plasmatreatment is generated with a solid state RF plasma source having ahelical ribbon electrode, and wherein the layer deposited by the firstreactant is treated; and c. repeating steps (a)-(b) until the thin filmcomprising a plurality of layers is deposited.
 21. An apparatus toperform nano-layer deposition (“NLD”), comprising: an inductivelycoupled solid state RF plasma source that can generate a plasma, theplasma source comprising a helical ribbon electrode and a generator; anda process chamber associated with the plasma source, wherein a device isexposed to a gaseous first reactant in the chamber, so that the firstreactant deposits on the device to form a layer, and wherein in thechamber of gases, the device, coated with the first reactant, is exposedto a gaseous second reactant under plasma, to treat the layer depositedby the first reactant.
 22. An apparatus to perform nano-layerdeposition, comprising: an inductively coupled solid state RF plasmasource that can generate a plasma, the plasma source comprising ahelical ribbon electrode and a generator; and a process chamberassociated with the helical ribbon electrode, the chamber adapted toenclose a device to be exposed to a gaseous first reactant, the firstreactant for forming a layer on the device, the chamber further adaptedto be purged of the first reactant, and to accept a second reactantunder plasma to treat the device coated with the first reactant.
 23. Animproved process to deposit a thin film on a substrate, the improvementcomprising successively depositing a plurality of layers made of atleast one reactant selected from the group consisting of metal organic,organic, metal, metal nitride, and metal oxide, with each of said layersbeing greater than one atomic layer thick.
 24. An improved method ofthin film processing, the improvement comprising depositing multipleatomic layers for each exposure to a reactant for high throughputprocessing.
 25. An improved method for thin film processing, theimprovement comprising using nano-layer deposition to create ananocrystalline grain structure in an amorphous matrix.
 26. An improvedmethod for semiconductor thin film processing, the improvementcomprising incorporating in a plasma excitation circuit a helical ribbonelectrode adapted to enhance the plasma uniformity.
 27. A method forprocessing a thin film onto a semiconductor wafer, the methodcomprising: exposing a wafer in a chamber with a first gaseous reactant;coating the wafer with the first reactant so that a first coat of thefirst reactant is greater than one monolayer in thickness; evacuatingthe chamber; exposing the coated wafer to a gaseous second reactant as aplasma; and forming a second coat over the first coat, the second coatbeing greater than one monolayer in thickness.
 28. The method as inclaim 27 wherein the method further comprises successively adding atleast one additional coat by repeating the evacuating step, the secondexposing step, and the forming step.
 29. The method as in claim 27wherein the method further comprises exciting the plasma with a solidstate RF plasma source functionally associated with the chamber.
 30. Themethod as in claim 27 wherein the exciting step uses a helical ribbonelectrode, as the solid state RF plasma source.
 31. The method as inclaim 27, wherein the plasma has a density higher than 5×10⁹ ion/cm³.32. The method as in claim 27 wherein the method further comprisesperforming the second exposing step under pressure above 100 mT.
 33. Themethod as in claim 27 wherein the second exposing step and subsequentforming step further comprise reacting the first coat of the firstreactant with the second coat of the second reactant to form a differentchemical product.
 34. The method as in claim 27 wherein the method isunaffected by self-limiting surface reactions of the first coat andsecond coat.
 35. The method as in claim 28 wherein the method isunaffected by self-limiting surface reactions of the first coat, thesecond coat, and the at least one additional coat.
 36. The method as inclaim 27 wherein the method further comprises carrying out the methodusing a multi-chamber processing system that is adapted to receive andprocess a plurality of wafers, wherein the wafers are transferred todifferent chambers.
 37. A method for processing a thin film onto aplurality of semiconductor wafers using a multi-chamber processingapparatus, the method comprising: loading the plurality of wafers into afirst area of the apparatus; evacuating the first area; delivering theplurality of wafers to a second chamber; transferring at least one waferto a third chamber for processing; processing the at least one wafer byexposing the at least one wafer in the third chamber to a first gaseousreactant; coating the at least one wafer with the first reactant so thata first coat of the first reactant is greater than one monolayer inthickness; evacuating the third chamber; exposing the coated wafer to agaseous second reactant as a plasma; and forming a second coat over thefirst coat, the second coat being greater than one monolayer inthickness.
 38. The method as in claim 37 wherein the loading step placesthe plurality of wafers into a load lock.
 39. The method as in claim 37wherein the delivering step places the plurality of wafers into atransfer chamber.
 40. The method as in claim 37 wherein the transferringstep comprises purging the transfer chamber during transfer of at leastone of said plurality of wafers during transfer from a transfer chamberto a processing chamber.
 41. The method as in claim 37 wherein the thedelivering step comprises purging the transfer chamber during transferof at least one of said plurality of wafers from a loading lock to atransfer chamber.
 42. An apparatus for semi-conductor thin filmprocessing, the apparatus comprising: a plasma excitation circuit drivenby an inductively coupled plasma generator; and a processing chamberfunctionally associated with the plasma excitation circuit, wherein theprocessing chamber is sealed for successively processing a substrate aplurality of times with at least one species of gas.
 43. An apparatus asin claim 42 wherein the plasma excitation circuit further comprises ahelical ribbon electrode.
 44. An apparatus as in claim 43 wherein thehelical ribbon electrode is connected with a generator; the helicalribbon electrode rests above a dielectric wall; and the dielectric wallrests above the chamber and is supported by at least one chamber wall,wherein the dielectric wall allows energy from the generator to passthrough a plasma inside the chamber.
 45. An apparatus as in claim 44wherein the dielectric wall is made from a material selected from thegroup of non-metallic materials comprising ceramics, glass, quartz orplastic.
 46. An apparatus as in claim 44 wherein the helical ribbonelectrode is connected with a generator and the helical ribbon electrodeis positioned inside the chamber.
 47. An apparatus as in claim 46wherein the generator drives the helical ribbon electrode via anelectrical feed.
 48. An apparatus as in claim 43 wherein the helicalribbon electrode is connected with a generator; the helical ribbonelectrode is wrapped around a tubular dielectric wall; and the chamberis positioned within the helical ribbon electrode and the tubulardielectric wall.
 49. An apparatus as in claim 45 wherein the distancebetween the helical ribbon electrode and the substrate is less than 5inches.
 50. An apparatus as in claim 49 wherein the chamber is elongatedwith a vertical axis of the chamber less than a horizontal axis of thechamber.
 51. The apparatus as in claim 43 wherein the helical ribbonelectrode includes a coil, and said coil has between 3 to 10 turns. 52.The apparatus as in claim 43 wherein the helical ribbon electrode ismade of a conductive ductile metal.
 53. The apparatus as in claim 52wherein the conductive ductile metal is copper.
 54. The apparatus as inclaim 52 wherein the conductive ductile metal is aluminum.
 55. Theapparatus as in claim 51 wherein a width of the coil is greater than athickness of the coil.
 56. The apparatus as in claim 55 wherein a ratioof the width to the thickness of the coil is at least 100:1.
 57. Theapparatus as in claim 55 wherein a ratio of the width to the thicknessof the coil is between 100:1 to 10,000:1.
 58. The apparatus as in claim43 wherein: the helical ribbon electrode includes a conductive coil; thecoil has a plurality of turns; the helical ribbon electrode iscompressed so that each of the plurality of turns of the coil has a topflat surface and a bottom flat surface; and the coil is insulated by aplurality of sheets of a dielectric material wherein a width of the coilis smaller than a width of the dielectric sheet, and one surface of eachof the turns of the compressed coil engage one side of one of theplurality of the dielectric sheets.
 59. An apparatus as in claim 42wherein the plasma excitation circuit further comprises an externalelectrode selected from the group consisting of capacitance couplingtype and inductance coupling type.
 60. An apparatus as in claim 42wherein the apparatus includes a heat exchanger adapted to remove heatfrom the plasma excitation circuit during operation.
 61. An apparatus asin claim 42 wherein the plasma generator is functionally associated witha controller, wherein the controller generates a periodic pulse, tocontrol on/off plasma generation.
 62. An apparatus for semi-conductorthin film processing having a plurality of chambers, the apparatuscomprising: a plasma excitation circuit driven by an inductively coupledplasma generator; a load lock to flush ambient air from at least onewafer to be processed in the apparatus; a transfer chamber for receivingthe at least one wafer from the load lock; and a processing chamber thatreceives the at least one wafer from the transfer chamber, theprocessing chamber also being functionally associated with the plasmaexcitation circuit, wherein the processing chamber is sealed forsuccessively processing the at least one wafer a plurality of times withat least one species of gas.
 63. The apparatus of claim 62 furthercomprising a first slit valve between the load lock and the transferchamber.
 64. The apparatus of claim 62 further comprising a second slitvalve between the transfer chamber and the processing chamber.
 65. Theapparatus of claim 62 wherein the load lock further comprises an aircirculation and filtration system to flush the ambient air surroundingthe at least one wafer.
 66. The apparatus of claim 62 wherein the loadlock further comprises at least one pressure sensor.